Rheological properties of apple flesh pomace pectins extracted by four methods

Apple flesh pomace pectins were extracted by traditional acid method (TA) , cellulase method (CL) , ultrasound-assisted method (UA) and microwave-assisted method (MA) and identified. The effects of shearing rate, concentration, temperature, and storage time on the rheological properties of pectins were investigated. In addition, viscosity-average molecular weights of pectins were measured to verify their rheological characterization.The results showed that the apparent viscosity of pectins dropped with the increase of shearing rate, which belonged to pseudo-plastic fluid behavior of typical non-Newtonian fluid. The shear thinning behavior was more obvious at high concentration. The increase of temperature and storage time extension led to a decrease of apparent viscosity of the pectin solution. The apparent viscosity and the viscosity- average molecular weights of the four pectins showed the following order:TA >CL >UA >MA, the rheological properties of apple pectin was successfully verified by the viscosity-average molecular weights.